Modern electronic devices, such as computer systems, storage systems, communications systems, and so forth, employ relatively high-speed communications links. A communications link (e.g., a bus, a network link, etc.) can be made up of different combinations of communications media, such as conductive traces on a circuit board, cables, connectors, and so forth. There may be many different possible combinations of different media for implementing communications links.
A driver interface that transmits and receives signals over a communications link is typically associated with tunable parameters that are set according to the combination of communications media in the communications link. A communications link that includes different media can experience reflections due to changes in the media type. Moreover, different media types can exhibit different propagation losses. The tunable parameters of a driver interface are set to values to optimize (or to ensure proper operation of) the communication of signals over the communications link that includes some combination of different media.
For each combination of different media that make up a communications link, a unique set of parameter values for the driver interface is determined, usually by running a number of tests in a laboratory. Once the parameter values are determined, such parameter values can be stored within a system in which the communications link is present. The stored parameter values are used to provide the settings for the corresponding driver interface during system operation.
It is possible that portions of a communications link may be changed during the life of the system, such as for maintenance or repair purposes. For example, if one cable is replaced with another cable, it is possible that the characteristics of the new cable may differ from those of the original cable. This may cause the predefined parameter values for the corresponding driver interface to no longer be valid, which can adversely affect reliability and performance of communications links in the system.